The issue of high definition audio in the television broadcast of sporting events
The diagram of the typical mass international sporting event, like a football match in Serie A, reports a very complex sound setup, ad Dolby European managers Ignacio Díaz-Valdés Alonso, Broadcast Systems Engineer, and Philip Arletti, Country Manager Italy, recently described in a press conference in Milan.
Starting from many microphones placed in strategic locations. There are four omni-directional microphones to recreate a realistic environment. They are placed at the four corners of the field to capture to the roar of the audience; then other specific microphones capture the audio in the foreground and are highly directional, super-cardioid "shotguns" located on the 4 sides of the perimeter of the playing court capture sounds even at 20, 30 meters away with incredible precision, including the curses and insults of referees, players and coaches, if any.
These super directional microphones follow the action, then the engineer will open some and closes others for this purpose.
Six directional microphones are placed for each longer side of the gridiron including two in the vertices in co-presence with minor sides; four are always placed at regular intervals on the shorter sides of the field, for a total of 16 microphones.
To complete the setup a Soundfield microphone is placed on the stand used for the cameras along the main line to center field, and another stereo microphone is in the same position.
The Soundfield microphone contains 4 capsules inside, placed in a special static support in order to record sounds coming from any direction and -along with a proper external processor – it is capable of producing a multi-channel audio omnidirectional 5.1 signal.
The Moto GP
A completely different situation instead is seen in MotoGP in which the position of the microphones must perform a dynamic shooting even from "fixed" locations.
The sound stage is complicated both from the point of view of the video and audio.
In the mentioned meeting the set-up planned for the next edition of the Moto GP was described. It is generally considered very problematic to create a good stereo image in such cases, and even more especially in terms of shooting to 5.1 channels.
Much care has been taken in the preparation to break away from the previous edition -two years ago- in which the sound was not sure exciting.
In fact, in the past each camera had two-channel audio with a microphone following the action placed right on the camera and a second positioned shooting in a fixed position about twenty meters from the passing bikes, so the sound in practice was not stereo.
Today, however, for the next edition it is decided to use a pair of stereo microphones fixed on each camera so to place in the right environment of the circuit the exact proportion of incoming sound to our ears. So, basically, every interesting point of the circuit will be followed with a pair of microphones in stereo.
When switching between the various cameras, the sound follows the pictures and you get a significant presence effect.
For the surround it was created first of all a "bed" of the ambience of the listening audience by placing microphones fixed at strategic points (B, E, D, C, in the red points).
Moreover, since in each circuit some video wall showing the action away to the public are installed, the actual emotional reactions of the audience for each event in the track can be taken from that single location.
A 5.1 microphone was also placed along the finish line.
Each camera takes up the bike that crosses the finish line and the effect of the enveloping surround sound expands everywhere so exciting.
In practice for the next season it is expected to put on the track as many as 34 microphones, 32 Audiotechnica (15 units 815B and 16 units 8035B, a stereo model 825), a stereo mike by Shure and one stereo by Sennheiser model 418.
At home
So, huge technologies for audio are planned for Moto GP but the problem remains at home as tv flat panels with speakers inside are scarce and the total loss of the surround effect is only partially solved by making use of so-called soundbars, optional arrays of external loudspeakers which manage to combine a good wrap-around effect with high quality in sound at reasonable price, generally.
The set up on the circuit still is a compromise between cost and performance, in fact if you were using all surround microphones you would have an even more comprehensive multichannel sound image, but certainly unbalanced in the cost-performance ratio.
From an artistic point of view it is possible to switch between the many cameras to have also the front audio of each shot, but to maintain the ambience coming from only one fixed omnidirectional microphone.
Actually it would be useless to reproduce the sound from the rear point of view of each camera.
This concept is also valid in football as described above.
